Let me Google that for you. (http://lmgtfy.com/?q=1557m+hotblast+furnace)

This took about three seconds to find.

Click on the first hit on the Google page.
Then click on Downloads.
Then click on Owners Manuals
Then click on 1557.pdf


OR... just click on the second hit on that Google page. It is direct to the manual.


Without a blower no voltage is required.
With a blower 120v is required.